1. Field of the Invention
The present invention relates to a rigid computer memory disc manufacturing method and, more particularly, to a method of supporting a rigid computer memory disc so that manufacturing operations may be performed thereon.
2. Description of the Prior Art
The present invention relates to the manufacture of rigid computer memory discs of the type which are used with a memory apparatus of a computer for storing data thereon. These discs are typically made of an aluminum alloy, have an inner diameter of 1.576 inch, an outer diameter of 5.118 inches, and a thickness of 0.075 inch. The opposed surfaces of the discs are coated with a magnetic coating for memory use.
In the usual method of manufacturing rigid computer memory discs, the inside and outside diameters are sized to the proper dimensions. Then the faces of the disc blank are turned on a lathe and subsequently polished to a super-fine finish. Some operations, such as turning the faces on a lathe, are done using a vacuum chuck which holds one face of the disc blank while the lathe operates on the opposite face thereof. Other operations, particularly those that require operations on both faces at the same time, require that some clamping be done to the disc. Such clamping is typically done by a ring having a width of approximately 0.25 inch which holds the disc very near its inside diameter. This means that the area of the disc face that is under the clamp cannot have any operations performed on it, such as a finishing or turning operation.
These methods of manufacturing rigid computer memory discs have a number of disadvantages when a clamp is used, since the area under the clamp cannot have any operations performed thereon. If this method is used for surface finishing, a step in the surface of the disc results and this is undesirable. While this can be eliminated by using a vacuum chuck, the result here is that only one surface of the disc can be processed at one time The ability to perform operations simultaneously to both faces and over the entire surface of the disc is an advantage because it greatly reduces the time required to perform a given operation in the manufacture of a computer memory disc substrate. This has been unachievable heretofore.